如果想查看當(dāng)前連接在哪個(gè)數(shù)據(jù)庫

下面，可以直接輸入db

> db

Admin

想切換到test數(shù)據(jù)庫下面

> use test

switched to db test

> db

Test

想查看test下有哪些表或者叫collection，可以輸入

> show collections

system.indexes

user

想知道m(xù)ongodb支持哪些命令，可以直接輸入help

> help

HELP

         show dbs                     show database names

         show collections             show collections in current database

         show users                   show users in current database

         show profile                 show most recent system.profile entries with time >= 1ms

         use <db name>                set curent database to <db name>

         db.help()                    help on DB methods

         db.foo.help()                help on collection methods

         db.foo.find()                list objects in collection foo

         db.foo.find( { a :  } )     list objects in foo where a ==

         it                           result of the last line evaluated; use to further iterate

如果想知道當(dāng)前數(shù)據(jù)庫支持哪些方法：

> db.help();

DB methods:

         db.addUser(username, password) 添加數(shù)據(jù)庫授權(quán)用戶

         db.auth(username, password)                訪問認(rèn)證

         db.cloneDatabase(fromhost) 克隆數(shù)據(jù)庫

         db.commandHelp(name) returns the help for the command

         db.copyDatabase(fromdb, todb, fromhost)  復(fù)制數(shù)據(jù)庫

         db.createCollection(name, { size : ..., capped : ..., max : ... } ) 創(chuàng)建表

         db.currentOp() displays the current operation in the db

         db.dropDatabase()        刪除當(dāng)前數(shù)據(jù)庫

         db.eval(func, args) run code server-side

         db.getCollection(cname) same as db['cname'] or db.cname

         db.getCollectionNames()        獲取當(dāng)前數(shù)據(jù)庫的表名

         db.getLastError() - just returns the err msg string

         db.getLastErrorObj() - return full status object

         db.getMongo() get the server connection object

         db.getMongo().setSlaveOk() allow this connection to read from the nonmaster member of a replica pair

         db.getName()

         db.getPrevError()

         db.getProfilingLevel()

         db.getReplicationInfo()

         db.getSisterDB(name) get the db at the same server as this onew

         db.killOp() kills the current operation in the db

         db.printCollectionStats()   打印各表的狀態(tài)信息

         db.printReplicationInfo()        打印主數(shù)據(jù)庫的復(fù)制狀態(tài)信息

         db.printSlaveReplicationInfo()        打印從數(shù)據(jù)庫的復(fù)制狀態(tài)信息

         db.printShardingStatus()                打印分片狀態(tài)信息

         db.removeUser(username) 刪除數(shù)據(jù)庫用戶

         db.repairDatabase() 修復(fù)數(shù)據(jù)庫

         db.resetError()

         db.runCommand(cmdObj) run a database command.  if cmdObj is a string, turns it into { cmdObj :  }

         db.setProfilingLevel(level) =off =slow =all

         db.shutdownServer()

         db.version() current version of the server

如果想知道當(dāng)前數(shù)據(jù)庫下的表或者表collection支持哪些方法，可以使用一下命令如：

> db.user.help();  user為表名

DBCollection help

         db.foo.count()                統(tǒng)計(jì)表的行數(shù)

         db.foo.dataSize()        統(tǒng)計(jì)表數(shù)據(jù)的大小

         db.foo.distinct( key ) - eg. db.foo.distinct( 'x' )                按照給定的條件除重

         db.foo.drop() drop the collection 刪除表

         db.foo.dropIndex(name)  刪除指定索引

         db.foo.dropIndexes() 刪除所有索引

         db.foo.ensureIndex(keypattern,options) - options should be an object with these possible fields: name, unique, dropDups  增加索引

         db.foo.find( [query] , [fields]) - first parameter is an optional query filter. second parameter is optional set of fields to return. 根據(jù)條件查找數(shù)據(jù)

                                            e.g. db.foo.find( { x :  } , { name :  , x :  } )

         db.foo.find(...).count()

         db.foo.find(...).limit(n) 根據(jù)條件查找數(shù)據(jù)并返回指定記錄數(shù)

         db.foo.find(...).skip(n)

         db.foo.find(...).sort(...) 查找排序

         db.foo.findOne([query]) 根據(jù)條件查詢只查詢一條數(shù)據(jù)

         db.foo.getDB() get DB object associated with collection  返回表所屬的庫

         db.foo.getIndexes() 顯示表的所有索引

         db.foo.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } ) 根據(jù)條件分組

         db.foo.mapReduce( mapFunction , reduceFunction , <optional params> )

         db.foo.remove(query) 根據(jù)條件刪除數(shù)據(jù)

         db.foo.renameCollection( newName ) renames the collection  重命名表

         db.foo.save(obj) 保存數(shù)據(jù)

         db.foo.stats()  查看表的狀態(tài)

         db.foo.storageSize() - includes free space allocated to this collection 查詢分配到表空間大小

         db.foo.totalIndexSize() - size in bytes of all the indexes 查詢所有索引的大小

         db.foo.totalSize() - storage allocated for all data and indexes 查詢表的總大小

         db.foo.update(query, object[, upsert_bool]) 根據(jù)條件更新數(shù)據(jù)

         db.foo.validate() - SLOW 驗(yàn)證表的詳細(xì)信息

         db.foo.getShardVersion() - only for use with sharding